1. Technical Field of the Invention
The present invention relates to a low power consumption type automobile-mounted controller, and more particularly to a low power consumption type automobile-mounted controller capable of reducing power consumption of an automobile-mounted power source by disconnecting a connection of the automobile-mounted power source to a microcontroller unit while an automotive engine is kept in a stopped state for many hours.
2. Prior Art
Generally, an automobile-mounted controller mounted on an automobile, for operating each portion of the automobile, is provided with one or more microcontroller units (MCU) for controlling the entire automobile-mounted controller. This microcontroller unit is set to a normal operation mode of executing its original control operation while the ignition switch is turned ON and the automotive engine is operating, but while the ignition switch is turned OFF and the automotive engine is stopped, the microcontroller unit is set to a sleep (standby) operation mode of selectively executing only a specific control operation.
When the microcontroller unit has been set to the sleep operation mode, the automobile-mounted power source has been connected to a power supply port, but power consumption of the automobile-mounted power source in the microcontroller unit is little because the original control operation is not performed. For this reason, the automobile-mounted controller is set to an operation mode having slight power consumption of the automobile-mounted power source, that is, the low power consumption mode.
While the ignition switch is turned OFF and the automotive engine is stopped, the known automobile-mounted controller has been set to the low power consumption mode for the time being, but the power consumption in the automobile-mounted power source is continuing although little by little because the automobile-mounted power source has been connected to the power supply port of the microcontroller unit.
If an automobile has not been used over a long term by transporting the automobile or due to some other circumstances, the automotive engine is also maintained at a stopped state, and for that reason, charging for the automobile-mounted power source is not performed. Therefore, power consumption of the automobile-mounted power source continues even by power consumption of the automobile-mounted controller little by little. Thus, when the power consumption in the automobile-mounted power source has continued, if an attempt is made to start the engine on using the automobile, output voltage from the automobile-mounted power source has dropped lower than the rated voltage value, thus possibly causing the unexpected such as failure to start the engine.
The present invention has been achieved in the light of the above-described technical background, and is aimed to provide a low power consumption type automobile-mounted controller capable of switching so as to prevent power consumption in the automobile-mounted power source from continuing while the automobile has not been used over a long term.
In order to accomplish the above-described object, a low power consumption type automobile-mounted controller according to the present invention is provided at least with: a microcontroller unit having a power supply port, a voltage detection port, a control port, a communication port, and an input port; a first power supply path connected to the automobile-mounted power source through a change-over switch for turning ON/OFF the power supply port; a second power supply path for connecting the power supply port to the automobile-mounted power source through a controllable switch; and power open/close command means for turning ON/OFF the controllable switch in response to a power close command signal or a power open command signal in such a manner that on receipt of a power open command signal while the first power supply path is intercepted by turning OFF the change-over switch, the power open/close command means turns OFF the controllable switch to intercept the second power supply path.
In a first concrete example using the above-described structure, the power open command signal is supplied from another microcontroller unit connected to the microcontroller unit through a communication line.
In a second concrete example using the above-described structure, the power open command signal is supplied when a second change-over switch connected to the microcontroller unit is turned ON.
In a third concrete example using the above-described structure, the power open command signal is supplied when the change-over switch is turned OFF.
In a fourth concrete example using the above-described structure, the power open command signal is supplied when voltage detection output from voltage detection means of the automobile-mounted power source connected to the second power supply path lowers to lower than a predetermined value.
In the other concrete samples using the above-described structure, the change-over switch is an ignition switch.
According to the low power consumption type automobile-mounted controller using the above-described structure, while the first power supply path is intercepted by turning OFF the change-over switch, that is, when a power open command signal is generated and is supplied to the power open/close command means while the ignition switch is turned OFF and the automotive engine is stopped, the power open/close command means supplies a switch-off signal to the controllable switch and turns OFF the controllable switch to intercept the second power supply path, whereby the connected state between the power supply port of the microcontroller unit and the automobile-mounted power source is cut off, and the microcontroller unit is set to a super-low power consumption operation mode of eliminating any slight power consumption in the automobile-mounted power source. As a result, the power consumption in the automobile-mounted power source does not continue even if the automobile has not been used over a long term, and it is possible to prevent the unexpected from occurring such as failure to start the engine owing to lowered output voltage from the automobile-mounted power source when reusing the automobile.